Generally, overlay error of a via structure to a previous layer structure may adversely affect a critical dimension of the via structure. For example, overlay error may reduce a critical dimension of a via structure such that the via doesn't etch to full depth, or can't be filled with metal, or the via is functional but suffers from higher resistance compared with an aligned via.
For simplicity and/or clarity of illustration, elements illustrated in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, if considered appropriate, reference numerals have been repeated among the figures to indicate corresponding and/or analogous elements.